$(function(){
  let $btn = $('input'),
      delay = 6,
      timer = null;               

  $btn.val('同意 (' + delay + 's)');
  $btn.attr('disabled','disabled');
  
  timer = setInterval(()=>{
    $btn.val('同意(' + --delay + 's)');
    if(delay == 0){                                                 clearInterval(timer);
      $btn.val('同意');
      $btn.removeAttr('disabled');
    }
  },1000);
    
    $btn.click(()=>{
      alert('button clicked!')
    })
})
